418  
FNUS74 KHUN 151250  
FWSHUN  
 
SPOT FORECAST FOR GRAYSON SITE PREP...USFS  
NATIONAL WEATHER SERVICE HUNTSVILLE AL  
650 AM CST WED NOV 15 2017  
 
FORECAST IS BASED ON IGNITION TIME OF 0900 CST ON NOVEMBER 15.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION
 
 
MOISTURE GRADUALLY INCREASES THROUGH THE DAY WITH WINDS INITIALLY  
OUT OF THE SOUTH TURNING TO THE SOUTHWEST IN THE AFTERNOON AND  
EVENING. A SYSTEM TO OUR NORTH WILL PUSH A COLD FRONT INTO THE  
AREA LATE THIS EVENING. AN ISOLATED LIGHT SHOWER IS POSSIBLE ALONG  
THE FRONT BUT THE BETTER RAIN CHANCES WILL REMAIN TO THE NORTH  
OF SITE. MIXING HEIGHTS THIS AFTERNOON RANGE FROM 2,300-3,000 FEET.  
A FEW BRIEF GUSTS OF 12-15 MPH ARE POSSIBLE AT TIMES THIS AFTERNOON.  
TONIGHT WINDS SHIFT TO THE NW BEHIND THE FRONT BUT SPEEDS REMAIN  
BELOW 5 MPH. DRIER AIR BEGINS TO FILTER INTO THE AREA THURSDAY  
AND MINIMUM RH VALUES COULD LOWER TO 40-45 PERCENT. DISPERSION WILL  
BE FAIR TODAY WITH INCREASED TRANSPORT WINDS BUT GENERALLY POOR ON  
THURSDAY DUE TO A COMBINATION OF MIXING HEIGHTS AND WEAKER TRANSPORT  
WINDS.  
 
   
REST OF TODAY
 
 
SKY/WEATHER.........PARTLY SUNNY (60-70 PERCENT).  
MAX TEMPERATURE.....AROUND 62.  
MIN HUMIDITY........52 PERCENT.  
WIND (20 FT)........SOUTHWEST WINDS 5 TO 8 MPH IN THE LATE MORNING  
AND AFTERNOON, BECOMING LIGHT.  
CWR.................10 PERCENT.  
MIXING HEIGHT.......900-2500 FT AGL.  
TRANSPORT WINDS.....SOUTHWEST 10 TO 13 MPH.  
LVORI...............2.  
 
TIME (CST) 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........PC PC PC PC MC MC MC MC MC  
WEATHER COV.....  
WEATHER TYPE....  
TEMP............50 54 57 60 61 62 62 61 59  
RH..............77 69 62 55 53 52 52 53 60  
20 FT WIND DIR..170 170 180 190 190 200 200 210 210  
20 FT WIND SPD..7 8 8 7 7 6 6 5 3  
20 FT WIND GUST.10 10 10 8 8 7 6 5  
MIX HGT (KFT)...0.9 1.2 1.6 2.0 2.2 2.3 2.3 2.1 1.8  
TRANSP WIND DIR.160 170 180 180 190 200 210 210 210  
TRANSP WIND SPD.10 10 12 12 12 13 13 13 12  
DISPERSION IDX..9 9 24 29 31 35 34 32 27  
LVORI...........3 3 3 1 1 1 1 1 1  
CWR.............0 0 0 0 10 10 10 10 10  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT). A SLIGHT CHANCE  
OF SHOWERS EARLY IN THE EVENING.  
MIN TEMPERATURE.....AROUND 48.  
MAX HUMIDITY........100 PERCENT.  
WIND (20 FT)........LIGHT WINDS.  
CWR.................20 PERCENT, DECREASING TO 10 PERCENT IN THE  
LATE EVENING AND OVERNIGHT.  
MIXING HEIGHT.......1400-2200 FT AGL.  
TRANSPORT WINDS.....NORTH 7 TO 10 MPH.  
LVORI...............5.  
 
TIME (CST) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........MC MC MC MC MC MC MC MC MC MC MC MC  
WEATHER COV.....SCH SCH SCH  
WEATHER TYPE....RW RW RW  
TEMP............57 56 55 54 53 52 51 51 51 50 49 48  
RH..............64 69 72 77 80 83 86 86 89 93 96 100  
20 FT WIND DIR..210 220 220 220 230 240 270 300 320 330 340 350  
20 FT WIND SPD..3 3 3 3 2 2 2 2 3 3 3 3  
20 FT WIND GUST.4 4 4 4 4 5  
MIX HGT (KFT)...1.6 1.5 1.4 1.4 1.4 1.4 1.5 1.7 1.9 2.1 2.2 2.2  
TRANSP WIND DIR.220 220 240 250 250 260 270 280 310 330 330 350  
TRANSP WIND SPD.10 9 9 8 7 7 7 7 8 9 10 10  
DISPERSION IDX..21 18 17 15 12 13 3 3 4 4 5 7  
LVORI...........3 3 3 4 4 4 6 6 6 7 7 7  
CWR.............20 20 20 10 10 10 10 10 10 10 10 10  
   
THURSDAY
 
 
SKY/WEATHER.........PARTLY SUNNY (55-65 PERCENT), THEN BECOMING  
SUNNY (10-20 PERCENT).  
MAX TEMPERATURE.....AROUND 61.  
MIN HUMIDITY........47 PERCENT.  
WIND (20 FT)........LIGHT WINDS, BECOMING NORTH AROUND 5 MPH.  
CWR.................0 PERCENT.  
MIXING HEIGHT.......2100-2800 FT AGL.  
TRANSPORT WINDS.....NORTH 6 TO 10 MPH.  
LVORI...............4.  
 
TIME (CST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........MC MC MC MC MC MC MCR MCR MCR MCR MCR MCR  
WEATHER COV.....  
WEATHER TYPE....  
TEMP............48 49 50 52 54 56 58 60 61 60 58 55  
RH..............100 96 93 86 77 66 59 51 48 47 51 55  
20 FT WIND DIR..000 010 020 020 020 010 000 000 000 000 000 010  
20 FT WIND SPD..3 3 5 5 5 3 3 3 3 3 3 3  
20 FT WIND GUST.5 6 6 6 6 6 6 6 6 6 5 5  
MIX HGT (KFT)...2.2 2.3 2.3 2.4 2.5 2.6 2.6 2.7 2.8 2.7 2.5 2.1  
TRANSP WIND DIR.000 000 010 010 010 010 010 010 000 350 000 010  
TRANSP WIND SPD.10 10 9 8 7 7 6 6 6 6 6 7  
DISPERSION IDX..7 7 6 5 5 22 19 19 20 20 18 19  
LVORI...........6 6 6 4 4 4 2 2 2 2 2 2  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
 

 
FORECASTER...STUMPF  
REQUESTED BY...CLARK  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1718845.0/HUN  
.EMAIL KERRYCLARK@FS.FED.US  
 
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